The graph below appeared as part of an infographic published by a media company called Raconteur, which was distributed as a supplement to today’s copy of The Times.
The graph shows the spending on Product Lifecycle Management (PLM) by industry in the years 2013 and 2014 (presumably the 2014 values are estimates). The source of the data is credited as 2013 PLM Market Analysis Report, CIMdata.
The graph contains at least six problems:
- The order of the industry categories is apparently entirely arbitrary – the first four categories are in alphabetical order and then the sequence seems random. They are certainly not sorted by either the 2013 or 2014 values.
- The shape of the chart is therefore completely without meaning, since this would change if the order of the industry categories were altered in any way.
- It is not obvious until you study the numbers that the chart stacks the 2013 value on top of the 2014 value. Because the 2014 data is plotted as yellow hatched lines with the green background used to represent 2013 data behind them, it appears at first sight that 2014 has been overlaid on top of 2013.
- The individual data points are not plotted accurately. On studying the numbers, it appears that the values are plotted on the vertical lines to the left of each category label (numbered 1, 2, 3 etc). However, the cumulative data point for the first category is plotted at just under 8,000 (US$ million), but the values underneath sum to the overly precise $7,823.29.
- This lack of accuracy in plotting seems to be the result of connecting the data points using curved lines, just for the sake of smoothness.
- The values given by category do not add up to the totals stated in the legend at the top left of the graph – the ‘Other’ category has been excluded from the total.
So how would we recommend that the data is presented? That depends on the question we want the graphic to answer. The chart I created in Excel from the data in the infographic enables the values for 2013 and 2014 by industry category to be readily compared, and is sorted in order of 2014 spending. Whilst the portrayal of the data in my chart is hardly revolutionary, it seems to me to convey considerably more insight than the graph in the original infographic.